Just how Many Parts Do you Need?

Surface mount assembly robots are amazing machines. Not long ago, I read that the pick and place heads in the fastest, highest volume SMT machines travel so fast, that they are just short of supersonic. The placement logic takes into consideration the distortion and swing of the hardened steel head and nozzle, and deposits the component at just the right point in the deflection arc.

Our machines aren't that fast, but they're still pretty speedy. Speed demands precision. What does that have to do with parts quantity, you might ask?

The machines are precision devices, but the strips, reels, tubes, and trays that parts come in aren't. Parts can bounce around and move a bit within their packaging. SMT machines do their best to allow for that packaging slop, but all machines do sometimes miss. A miss-pick may result in a tiny part dropping off into the machine, rather than a solid placement on your board.

Assembly houses that require long reels to assemble from don't have to worry about a few lost parts, so no one ever hears about it. Screaming Circuits, however, wants to keep your costs down and convenience up, so we assembly from short cut strips of parts.

That's great, but our machines are still only robot, and like all robot beings, occasionally drop a part.

If you send us just the exact number of parts being placed on your boards and this happens, we won't have enough parts to finish building all of your boards. So, when you're sending us a parts kit, at minimum, we ask for 10% extra parts, with a minimum of ten, for each part in your BOM. For the super tiny 0201 parts, we ask for 50% extra.

Sending in extras gives us the best chance to deliver everything you need, without much extra cost on your end. For bigger parts, we like to see one extra.

Sunstone Circuits and Screaming Circuits work closely together to take as much stress as possible out of your prototype phase. You can quote and order assembly at Sunstone.com or at ScreamingCircuits.com.

Duane BensonWe are not hoarding all lost parts to combine into Forbin's giant world-dominating Colossus II computerNo, we are not. Really. We aren't.